Underreamer



Feb. 11, 1930. H. F. CLEM'ENT 1,746,694

UNDERREAMER Filed March 6, 1928 L l JIM Patented Feb. 11, 1930 vide andimproved arrangement of supports or carrying blocks for the reaming bitsor cuthaving UNITED STATES PATENT OFFICE HUBLEY F. CLEMENT, OF LONGBEACH, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, OF ONE-HALF T0 JOHNGRANT, OF LOS ANGELES, CALIFORNIA UNDEREEAMER Application filed March 6,1928. Serial No. 259,415.

My invention relates to an underreamer that is particularly designed foruse in deep wells for reaming or increasing the diameter of the wellhole in order to' permit the casing to be lowered as the drillingproceeds, and the principal objects of my invention are to generallyimprove upon and simplify the con.- struction of the existing forms ofunderreamers, and to provide simple and efficient means whereby thereaming bits or cutters will automatically move into expanded or reamingpositions as the reamer is lowered into position below the lower end ofthe eas- Further objects of my invention areto proters and to mount saidblocks or carriers 1n the body of the reamer so that they will bepositively guided during their movement from retracted toexpanded'position and vice versa; further, to provide an underreamerducts for the accommodation of the circulation of fluid duringunderreaming operations, and further, to provide simple and efiicientmeans whereby the reaming bits or cutters are expanded. or moved intoreaming positions under the influence of an expensive coil s ring.

With the oregoing and other objects in view, my invention consistsincertain novel features of construction and arrangement of parts thatwill be hereinafter more fully describe'd'and claimed and-illustrated inthe accompanying drawings in which:

'Fig. 1 is an elevational view of an underreamer of my improvedconstruction,

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal section taken on the line 33 of Fig. 1.

Fig. 4 is a horizontal section taken on the line 4-4: of Fig. 2. i

Fig. 5 is an elevational view of the inner face of the .lower portion ofone of the parts.

of the body of the underreamer.

Fig. 6 is a vertical section taken lengthwise thru the center of one ofthe bits or cutter carrying blocks.

Fig. 7 is an enlarged horizontal section taken on the line 7'--? of Fig.6.

Fig. 8 is a horizontal section taken on the line 8-8 in Fig. 2. I

Referring by numerals to the accompanying drawings which illustrate apractical embodiment of my invention, 10 designates the body of theunderreamer which is in the form of an elongated cylinder, and said bodybeing formed in two parts that are identical insize, form andconstruction and the joint or division line 11 between the two partsbeing on a longitudinally disposed medial plane. The parts of the bodyof the under reamer are detachably connected in any suitable manner,preferably by means of bolts 11 that pass thru the upper and lowerportions of the body on opposite sides of the axis thereof.

The upper portion of the body is slightly reduced in-diameter and thisreduced porany desired shape, either the fishtail type as shown or anordinary diamond point bit.

The inner portions of the two parts that form the body of theunderreamer are cut away a short distance above the bit 13 to form atransversely disposed chamber or opening 14 that is substantiallyrectangular in form and which accommodates the blocks or carriers forthe bits or cutters, and formed in the body 1Q immediately below thisopening is a pocket 15 that is adapted to receive the lower portions ofthe bit carriers when the latter are moved downward to retract the bitsor cutters. Formed in the inner faces of the two parts of the body 10,and leading downwardly from the pocket 15 to points on opposite sides ofthe upper portion of the bit 13 are fluid circulation ducts 16.

Formed in the side faces of the opening 14, adjacent to the. upper endthereof and within the pocket 15, are pairs of grooves 17 that areadapted to receive trunnions that project from the sides of the bit orcutter carrying blocks. The members of each pair of these grooves areinclined and they are arranged so that they diverge upwardly and themembers of the two upper pairs of grooves have greater inclination ordivergence than the members of the lower pairs (see Fig. 5). As a resultof this particular arrangement or inclination bf the pair of grooves,the upper ends of the bit or cutter carrying blocks will have a greaterdegree of inward and outward movement than the lower ends of saidblocks.

Arranged within the opening 14 is a pair of reamingbits or cuttercarrying blocks, each of which comprises an inner plate 18 and outwardlyprojecting end lugs 19. The intermediate portion of each plate 18 isprovided with a longitudinally disposed slot 20 which permits thepassage of circulation liquid, and seated in the lugs 19 and the ends ofa rod 21 upon which is loosely mounted a reaming bit or cutter 22,preferably of the type having longitudinally disposed ribs formed on itsouter surface.

In some instances, it may be found desirable to form each bit or cutterin two or more parts.

Extending horizontally thru each lug 19 is a pin or rod 23, the ends ofwhich project short distances beyond the side faces of the lugs, asillustrated in Fig. 7, and these projecting ends provide trunnions thatoccupy the corresponding grooves 17 in the body of the underreamer. Inorder to locate the rods 21 in the lugs 19, said rods 21 are providedwith notches 24 that receive the pins 23 when the latter are seated inthe lugs and thus the rods 21 are securely fastened to the lugs andtheir accidental displacement is effectually prevented.

The inner faces of the two parts of the body 10 of the underreamer abovethe openin 14 are recessed to provide a substantially cy indricalchamber 25, and extending lengthwise thru this chamber, is an axiallydisposed tube 26, the upper end of which communicates with an axiallydisposed circulation duct 27 that is formed in the upper end of thebody, and the lower end of this tube is clamped between the parts of thebody 10 immediately above the opening 14. In order to prevent this tube26 from becoming unseated and dropping downwardly into the opening 14,the lower end of said tube or that portion that is clam ed between theparts of the underreamer ody, is tapered as designated by 28, and theseat that accommodates said tapered lower end is correspondingly tapered(see Figs. 2 and 5).

Arranged for sliding movement on the upper portion of the tube 26 is aring shaped plate 29, and pivotally connected thereto on opposite sidesare the upper ends of rods 30 which latter extend downwardly thrugrooves 25" that are formed in the body 10 on opposite sides ofthechamber 25, and the lower ends of these rods 30 are pivotally connectedto the upper inner corners of blocks or cutters.

Surrounding tube 26, is an expansive coil spring 31, the upper end ofwhich bears against the underside of the ring 29 and the lower end ofsaid spring bears on a shoulder 32 that is formed within the body 10just above the tapered seat 28 for the lower end of tube 26 (see Figs. 2and 5).

Under normal conditions, the expansive power of spring 31 retains ring29 at the upper end of its travel within the chamber 25 and when sopositioned, the reaming bit or cutter carrying blocks are retained attheir upper limit of movement, as illustrated in Fig. 2 and due to theengagement of the trunnions in the pairs of grooves 17 and due to theinclination or angularity of said grooves, the bit or cutter carryingblocks, when at the upper limit of their movement, are in expanded orprojected positions.

When the underreamer is lowered into the well, the threaded upper end ofthe body of the reamer is connected to the lower end of the drill tubeand the reaming bit blocks are moved downwardly in the opening 14 untilthey occupy their retracted positions, and the reamer is now inserted inthe upper end of the casing and moved downwardly therethru, during whichmovement the reaming cutter bears against the inner face of the casingand due to the internal diameter of said casing, the cutters and theblocks carrying same are prevented from moving upwardly 1nto expandedpositions.

When the underreamer reaches a point below the lower end of the casing,the expansive power of spring 31 will act to move ring 29 upwardly,thereby drawing the reaming bit carrying blocks upwardly until the upperends of the blocks bear against the body of the underreamer above theopening 14 therein, and the trunnions in moving upwardly thru theinclined pairs of slots 17, will cause the blocks to move outwardlysimultaneously with their upward movement, and due to the fact that theupper pairs of grooves 17 have greater inclination than the lower pairs,the upper portions of the blocks will be moved outwardly to a greaterdegree than the lower portion. Thus, when said blocks are in expanded orreaming position, they will occupy inclined positions as illustrated inFig. 2.

As the underreamer is rotated, the bits or cutters 22 will engage andcut away the formation in the well hole below the lower end of thecasing, thereby accomplishing the desired underreaming operation andenabling the casing to be lowered as the drilling proceeds.

Circulation of water to carry off the cuttings from the underreamer ismade possible due to the provision of the duct 27, tube 26, opening 14,openings 20 in the inner walls of the reaming bit carrying blocks andthe ducts the bit carrying 16 that lead downwardly to the sides of thebit 13 that depends from the lower end of the underreamer.

When the underreamer is withdrawn from the well hole, the upwardmovement of said underreamer will bring the upper ends of theblocks'into engagement with the shoe in the lower end of the casing, andfurther upward movement of the underreamer will force the blocksdownwardly thru the opening 14 until the lower ends of said blocksoccupy the pocket 15 and due to the angularity of the pairs of'grooves17 in which the ends of the pins 23 travel, the blocks will be movedinwardly simultaneously with their downward movement, thereby permittingthe blocks and the bits carried thereby to enter the casing and to bedrawn upwardly therethru.

Thus, it will be seen that I have provided an underreamer that isrelatively simple in construction, inexpensive of manufacture and inwhich the reaming bits or cutters occupy slightly inclined positionswhen in expanded or cutting position, and which arrangement isespecially desirable due to the fact that the cutters act on theformation of angular line relative to the axis of the underreamer ratherthan on lines that are parallel with said axis.

It will be understood that minor changes in, the size, form andconstruction of the various parts of my improved underreamer may be madeand substituted for those herein shown and described without departingfrom the spirit of my invention, the scope of which is set forth in theappended claims.

I claim as my invention:

1. In an underreamer, a cylindrical body providedwith an opening, andthere being pairs of grooves formed in the body of the underreamer tothe sides of said opening, the members of the upper pairs of grooveshaving greater inclination than the members of the lower pairs ofgrooves, cutter carrying blocks arranged within said opening, andtrunnions projecting from said blocks into said grooves.

2. In an underreamer, a cylindrical body provided with an opening, andthere being pairs of grooves formed in the body of the underreamer tothe sides of said opening, the members of the upper pairs of grooveshaving greater inclination than the members of the lowerpairs ofgrooves, cutter carrying blocks arranged within said opening, trunnionsprojecting from said blocks into said grooves, and a spring for normallyholding said blocks at their upper limit of movement. 4

3. In an underreamer, a cylindrical body provided with an opening, apair of cutter carryingblocks arranged within said opening, pairs ofgrooves formed in the body of the underreamer to the sides of saidopening, the members of each pair of grooves diverging upwardly, themembers of the upper pairs of grooves having greater divergence than themembers of the lower pairs of grooves, and trunmons projecting from thecutter carrying blocks into said grooves.

4. In an underreamer, a cylindrical body provided with an opening, apair of blocks arranged for vertical and lateral movement within saidopening, a rotary cutter carried by each block, and there being acirculation opening formed thru each block to the rear of the cuttercarried thereby.

In testimony whereof I alfix my signature.

HURLEY F. CLEMENT.

